Page get reload after 2mins in Chrome and Firefox

HI All,

I am using RadAjaxPanle my aspx page and it is working good in IE. But in chrome after 2 mins idle time if any post back(submit button click, autopost back dropdown selection change) is happened to that page it is reloading again. Page.IsPost back is false after 2 mins Idle time post back.

I was checking IIS idle time out and cpu and memory ussages which are fine.

Please help if any known solutions for this problem.

Setting postback timeout as well in page load.

ScriptManager _scriptMan = ScriptManager.GetCurrent(this);
_scriptMan.AsyncPostBackTimeout = 36000;

<telerik:RadAjaxPanel ID="pnlMain" runat="server" LoadingPanelID="radAjaxLoadingPanelMain">...</telerik:RadAjaxPanel>